FeedingCancer pagurus is a large crab typical of hard and soft bottom communities. It is an active predator and consumes a variety of crustaceans (e.g. the green shore crab Carcinus maenas, the broad clawed porcelain crab Porcellana platycheles, the long clawed porcelain crab Pisidia longicornis, the hairy crab Pilumnus hirtellus and the squat lobster Galathea squamifera) and will also eat smaller members of their own species (conspecifics) (Lawton, 1989). Cancer pagurus also consumes a variety of molluscs e.g. the dog whelk Nucella lapillus, the winkle Littorina littorea (Lawton & Hughes, 1985), razor shells Ensis spp. (Hall et al., 1991), the blue mussel Mytilus edulis, the common cockle Cerastoderma edule and the oyster Ostrea edulis (Mascaro & Seed, 2001). Motile prey may be stalked and pounced upon, trapped under the abdomen and crushed with the chelae. Some prey is also ambushed from shelters under rocks (Lawton, 1989). In sediments Cancer pagurus may dig large pits to access bivalve molluscs such as Ensis sp. (Hall et al., 1991) and Lutraria lutraria. Cancer pagurus is mainly nocturnal, presumably to reduce predation by wolf fish, seals and cod (Skajaa et al., 1998).
Growth
Juveniles settle in the intertidal zone in late summer/ early autumn (Bennett, 1995) and remain there until they reach a carapace width (CW) of 6-7 cm (which takes about 3 years) before they move to subtidal areas (Regnault, 1994).
Growth rate varies with age and gender. Between years 4-8 of a male crabs life, it grows at about 1 cm CW per year. After the 8th year, growth rate slows gradually to about 2 mm per year between its 16th and 20th years. Female growth rate is less, at about 0.5 cm per year between years 4 and 8, declining to 0.1 cm per year between years 16 and 20 (Bennett, 1979).

Size can be related to depth. In less than 25 m of water, males and females have a mean CW of 14 cm. Between 25 and 55 m, males are on average 17 cm CW and females 15.8 cm, over 55 m these sizes increase to 18 cm CW for males and 17 cm CW for females (Brown & Bennett, 1980).

From Norway throughout the North Sea and English Channel to the coast of Portugal. Cancer pagurus may penetrate into the Mediterranean Sea and occur in the Black Sea (Anosov, 2000) but this is yet to be confirmed.

Mating is by copulation in spring and summer and occurs shortly after the female has moulted (Brown & Bennett, 1980). Females are 'berried' (carrying eggs under the abdomen) for 6-9 months after copulation and release the larvae in late spring/early summer (Thompson et al., 1995). Berried females do not feed, remaining in pits dug in the sediment or under rocks and are unlikely to be caught in a baited pot. As a result, fishing pressure does not affect larval supply (Howard, 1982). Fecundity is between 0.25 and 3 million eggs per female depending on size (Bennett, 1995). Females can store sperm and berried females retained after an experiment went on to produce viable larvae in the following reproductive season without moulting or copulating (Naylor et al., 1999). In the North Sea, berried females migrate offshore to release larvae and then move back inshore to feed (see larval general biology; Nichols et al., 1982).